Single-chamber compressed-air brake



Juif. 2.0 1931' w. HILDEBRAND SINGLE CHAMBER COMPRESSED AIR BRAKE FiledMarbh 15. .1930

Appnetiqhmeanarcnisgieao; seriainaaeasgemiliaemiiyjnanii,fiezs; p 1 fThis invention relates-to improvements in'l l fthe lctmstructionandoperation of compressed Y Lair brakes of the kindin which the release Vof :the fbrale can: `bel effected insuccessive 5 stages.,` fIn ffthesebrakes the controlling V member, besides being ,exposed to Avariable v'pressures inthe trainv pipe, `auxiliary*reseryoi'r," andb-rakecylinder, is `exposed to the l u pressure in a control chamber whichA is.only

lfflled whenl the brake Vis fullyV released, this latter pressure beingapproximately constant l fexcept for the immaterial variations of the v1 space in Vwhich it acts, caused bythe vmovements ofthe saidcontrolling member. lIn

lfkriown constuctionsthe control chamber has;

i l been provided witha non-return valveopeny lng towards'the interiorof ther chamberjand held on'its seat' by the pressure existing in thechamber when :the pressure inthe train pipe j braking operation. 'Such anon-return valve is not' always reliable, fand in Vthe event of itsbeing leaky its contents ina'y iow bac-k u into the train pipe or thelauxiliary reservoir,

1 sof-that after a quick succession'ofbraking'` `operations itbecomesexhausted. ,v AccordingV to this invention, the yregulation .lofV the filling of the control chamber is ef-` 'y l of the brake, thisyal-ve comprising a piston Whichon oneside isfeXposed te the variable Ygpressure inthe train pipe orjin theauxiliary a ""j'airlreservoirand'onmthe other sidetothe-pres 'sure existing 1n thecontrol chamber,vand a ception of -a braking "operation," the "slide '4071lquickly'shuts offfr the connection between` the control chamberandthetrain pipe o`r auXillary reservoir, in'which reduction of pres-l'-'r l Y V Y .effect 'of the brakacylinder pressure on` the moyementoftheslide Valve, ceases `before 'the' inletto the v control chamberis'again opened,

I-jso `that there is no danger lof the pressure inv l'tlrlc'auxiliaryreseryoror train pipe Which' for auxiliary reservoir r4is: reducedduring aA Y vto the`atinosphere.y lfected bylfa slide valve controllingtherelease l 'effgclearanoe is providedbetyveenthe-said'i'slidel p 1yalve and another piston exposed tothe brake j A.cylinder pressure',VTherefore uponv the in-) Sueis taking PlaCGfWhelebyany retirn ow;

ifthe contents of thechainb'er is prevented.V

Y .tonEK'cagainstthe pressure-of-thebrakeoylf` This arrangement hasv theadvantagethat the l f 1 inderga;

inases upon -release, in conjunction i Withfv thebrake cylinder pressure(at that tiineifde'-,Y creasing; vbut stillfeffective) fdispla'ci-ng the'A sli-de valye against ithejpressure. inthe control@y chamber'solitarir that the chamber; inletg is"` nH'Innniiinun;"or'frronrnnrnnnn' ERLIN; Yef'linlufiiNY'4 Value'.

:@rdertltiba `said?einen'tfnf'`nf.-sif clearly; understoodand-readilycarriedinto p l Veffect",.thexsarneWill now be described more I fullyWithf reference f to thev alcconipanyling` represented inthe: positionof'release". A

eryoirY pressure has Aattained its i1naxiniurrn drawingjfor Jdiagram.infwhich 'lthe brake is"` n iliary reservoir, Cfthe` brakefcylindenflithe train-pwe3@ slidevalveadiapted-tqpiaeerhe auxiliaryreservoir B`in,c'olninunicationpyvith Y the rake cylinder'through the conduit#C2;.S a; Y

a slide Valve controlling abroadinlet Matelica! sinall heightleadingpto'` the control.. chamber' A, Kaj; a piston operatiyelyjconnected by?V` its stem:y with the twofslides S 'and' Staand Koindicates a pistonjeiiposed tothebrale cylinf-.i l

derpressureQ UInjtlie positionlshown thewconk-fV Vduitclzisin'communicationthroughfjahollow l inthe :slidJyalyeSWitlifan'erhaustloutlet of V` effect the train pipfe'spressure isreduced,l then ment: ofthe;piston Kar/and ofthe'slides Saa 'upon thecommencelnentfoftheupwardilnove-*L f i e andsv the slide Sa Willfclosethe inlet aperi z tperture-ffov isjinterruptred.l Du'ringthefcoursestenror rodoii the controllinglpiston Ka'wfill at the same time lift thestein or rod of the piss stage-"the train-pipe pressure bejncreasedvthen, the I:brake *cylinder pressure existingf in the chamber above;Lthe pistonKc :co-operates vwith theniain pipe pressurepupomthe up- Vsoper part of the piston Ka toA effect the downward movement of the slidesS and Saa As soon as the former connects the outlet'o with Y -a smallbranch 01 of the conduit c2 an outthe braking action -can be reducedgradually step by step. That is to say, aftereach increase in train pipepressurethe piston Ka operates the slide valve Sito lapped positionuntil the train pipe pressurehas been'increased sufficiently to Ymovepiston Ka against the pressure in the control chamber A to releasedposition.

' c `Owing to the play provided for between the piston rods of thecontrolling piston Ka and of the piston Kc the pistonlcc reaches therklimit of its stroke before the piston Kal has terminated its downwardstroke', and con-I sequently the brake cylinder pressureffthen no longercoloperates in the displacement of the slides S and Sa; therefore the.slide *Sa can-not expose the inlet ofthe chamber A until the train pipepressure has attained its maximum value. In this yway the compressed yair contained in the chamber A is prevented from flowing back into thepipe, when the maximum pressure does Ynot yet prevail there,- in, thusavoiding` upon each occasion a loss of pressure in the chamber A, if theaugmentation of the pipe pressure is not carried out up. to its maximumvalue,` which might occur upon .maintaining a partial release of thebrake, or upon the inception of a new braking operation prior tocomplete release. 'Y What I claim and desireto secure by Letters'Patentof the United States is :e

1. Ina compressed air brake of the class c described, a train pipe, avalve casing commumcating with said plpe, a control chamber having aninlet to admit air'thereto from saidscasing. an auxiliaryfreservoir, abrake cylinder, a piston constantly' exposed to the,

`pressure in said ,chamber` and to the'ftrain pipe and having its stempositioned in said casing, a slide valve adapted toplace saidcylinder incommunication withsaidreservoir to apply the brake and withY an exhaustcommunication with. said reservoirtoV apply *f the brake andfwith anexhaust outlet to the atmosphere to release the brake, asecond Y Y .c 0Yslide valve spaced from-said plstonadapted '7 toclosethe control chamberinlet-when l'the Y brake is applied, said valves'being operative lyconnected tothe piston stem,and` a ,second `piston;exposedtojthe brakecylinder pres-` sure adapted *to "cooperateiwithf Vsaid first.

named piston, said second piston having a limitedi stroke to giveclearance from said first named piston when'the-brake is released.WILHELM HILDEBRAND.

ioo

outlet to the atmosphere to release the brake` Y and a second slidevalve spacedl from Vsaid piston adapted to close the control chamberinlet when the brake is applied, said'valves` being operativelyconnected tothe piston stem. i

2. In a compressed air brake of the class described, a train pipe, avalve casingc'ommunicating with said pipe, a control chamber l1avin,f'anY inlet to admit air thereto from said casing, an auxiliaryvreservoir, al brakecylinder, a piston constantly exposed to the pressurein said chamber and to the train pipe

